Object is hashable only if its hash value never changes during its lifetime (needs `__hash__()` method) and can be compared to other objects (needs `__eq__()` method). Hash values returned by `hash()` function are integers. Hash values are used to quickly compare dictionary keys during a dictionary lookup. ### See also 1. ### Reference 1. [Term Hashable on Python Docs](https://docs.python.org/3/glossary.html#term-hashable) 2. [hash() method - Python Docs](https://docs.python.org/3/library/functions.html#hash)